This is as much a question on botany as anything. It's inspired by looking at my olive tree, but I suppose the same question applies to all trees.
The trunk seems to come to an end at some point, and give way to a jumble of smaller branches. So how does the tree grow? Does one of those branches become the main trunk and grow from its tip, or does the existing trunk extend? Obviously the trunk grows thicker, but does it also grow taller? The branches are so all-over-the-place that I can't imagine a way that my olive tree could grow from any of its growing tips and still retain its vertical trunk structure.
Thanks for any insight.